Fix detect-targets on Linux and add CI testing (#1344)

* Testing: Add `detect-targets/src/main.rs`

Signed-off-by: Jiahao XU <Jiahao_XU@outlook.com>

* Fix `detect-targets` linux: `guess_host_triple` could return wrong libc info

so it has to check it manually instead of simply providing alternatives
like other OSes.

Signed-off-by: Jiahao XU <Jiahao_XU@outlook.com>

* Fix `get_ld_flavor` for Alpine's gcompat glibc

Its output is different from regular glibc, so we need to hardcode that
particular cases.

Signed-off-by: Jiahao XU <Jiahao_XU@outlook.com>

* Fix detection of alpine specific musl target

Signed-off-by: Jiahao XU <Jiahao_XU@outlook.com>

* Add ci testing for Alpine

Signed-off-by: Jiahao XU <Jiahao_XU@outlook.com>

* Add CI test for detect-targets on ubuntu

Signed-off-by: Jiahao XU <Jiahao_XU@outlook.com>

* Refactor `get_ld_flavor`

Signed-off-by: Jiahao XU <Jiahao_XU@outlook.com>

* Fix shellcheck

Signed-off-by: Jiahao XU <Jiahao_XU@outlook.com>

* Add more CI test for ubuntu

and fixed typo in it

Signed-off-by: Jiahao XU <Jiahao_XU@outlook.com>

* Rm distro specific target as it breaks `cargo-install` fallback

Signed-off-by: Jiahao XU <Jiahao_XU@outlook.com>

* Make sure all binaries are built in CI

Signed-off-by: Jiahao XU <Jiahao_XU@outlook.com>

* Add `package.metadata.binstall` for `detect-targets`

Signed-off-by: Jiahao XU <Jiahao_XU@outlook.com>

* Fix justfile

Signed-off-by: Jiahao XU <Jiahao_XU@outlook.com>

* Fix `detect-targets-{alpine, ubuntu}-test`

Signed-off-by: Jiahao XU <Jiahao_XU@outlook.com>

* Fix `detect-targets-ubuntu-test`

Signed-off-by: Jiahao XU <Jiahao_XU@outlook.com>

* Fix `debug-targets-ubuntu-test`

Signed-off-by: Jiahao XU <Jiahao_XU@outlook.com>

* `set -exuo pipefail` in `detect-targets-ubuntu-test`

Signed-off-by: Jiahao XU <Jiahao_XU@outlook.com>

* Simplify `detect-targets-*-test`: Use `Swatinem/rust-cache@v2` directly

instead of using `just-setup`

Signed-off-by: Jiahao XU <Jiahao_XU@outlook.com>

* Rm dup steps in `detect-targets-ubuntu-test`

Signed-off-by: Jiahao XU <Jiahao_XU@outlook.com>

* Add `ls` to detect-targets-alpine-test for debugging

Signed-off-by: Jiahao XU <Jiahao_XU@outlook.com>

* FIx `detect-targets-alpine-test`

Signed-off-by: Jiahao XU <Jiahao_XU@outlook.com>

* Fix `get_ld_flavor`

Signed-off-by: Jiahao XU <Jiahao_XU@outlook.com>

* Fix `linux::detect_targets` on ubuntu & glibc system

Signed-off-by: Jiahao XU <Jiahao_XU@outlook.com>

* FIx `linux::detect_targets` glibc checking

Check dynlib suffix

Signed-off-by: Jiahao XU <Jiahao_XU@outlook.com>

---------

Signed-off-by: Jiahao XU <Jiahao_XU@outlook.com>

.github/workflows/ci.yml

@@ -131,6 +131,39 @@ jobs:
       CARGO_PROFILE_RELEASE_LTO: no
       CARGO_PROFILE_RELEASE_CODEGEN_UNITS: 4
 
+  detect-targets-alpine-test:
+    runs-on: ubuntu-latest
+    env:
+      CARGO_BUILD_TARGET: x86_64-unknown-linux-musl
+      TARGET: x86_64-unknown-linux-musl
+    steps:
+    - uses: actions/checkout@v3
+    - name: Install x86_64-unknown-linux-musl target
+      run: rustup target add $TARGET
+    - uses: Swatinem/rust-cache@v2
+    - name: Build detect-targets
+      run: |
+        pip3 install -r zigbuild-requirements.txt
+        cd crates/detect-targets && cargo zigbuild --target $TARGET
+    - name: Run test in alpine
+      run: |
+        docker run --rm \
+          --mount src="$PWD/target/$TARGET/debug/detect-targets",dst=/usr/local/bin/detect-targets,type=bind \
+          --mount src="$PWD/test-detect-targets-musl.sh",dst=/usr/local/bin/test.sh,type=bind \
+          alpine test.sh "$TARGET"
+
+  detect-targets-ubuntu-test:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v3
+    - uses: Swatinem/rust-cache@v2
+    - name: Build detect-targets
+      run: cargo build --bin detect-targets
+    - name: Run test in ubuntu
+      run: |
+        set -exuo pipefail
+        [ "$(./target/debug/detect-targets)" = "$(printf '%s\n%s' x86_64-unknown-linux-gnu x86_64-unknown-linux-musl)" ]
+
   # Dummy job to have a stable name for the "all tests pass" requirement
   tests-pass:
     name: Tests pass
@@ -139,6 +172,8 @@ jobs:
     - cross-check
     - lint
     - release-builds
+    - detect-targets-alpine-test
+    - detect-targets-ubuntu-test
     if: always() # always run even if dependencies fail
     runs-on: ubuntu-latest
     steps:

crates/detect-targets/Cargo.toml

@@ -20,3 +20,6 @@ windows-dll = { version = "0.4.1", features = ["windows"], default-features = fa
 
 [dev-dependencies]
 tokio = { version = "1.28.2", features = ["macros"], default-features = false }
+
+[package.metadata.binstall]
+pkg-url = "{ repo }/releases/download/v{ version }/cargo-binstall-{ target }.full.{ archive-format }"

crates/detect-targets/src/detect.rs

@@ -38,19 +38,21 @@ pub async fn detect_targets() -> Vec<String> {
             .to_string()
     });
 
-    let mut targets = vec![target];
-
     cfg_if! {
         if #[cfg(target_os = "macos")] {
+            let mut targets = vec![target];
             targets.extend(macos::detect_alternative_targets(&targets[0]).await);
+            targets
         } else if #[cfg(target_os = "windows")] {
+            let mut targets = vec![target];
             targets.extend(windows::detect_alternative_targets(&targets[0]));
+            targets
         } else if #[cfg(target_os = "linux")] {
-            targets.extend(linux::detect_alternative_targets(&targets[0]).await);
+            // Linux is a bit special, since the result from `guess_host_triple`
+            // might be wrong about whether glibc or musl is used.
+            linux::detect_targets(target).await
         }
     }
-
-    targets
 }
 
 /// Figure out what the host target is using `rustc`.

crates/detect-targets/src/detect/linux.rs

@@ -1,12 +1,11 @@
 use std::{
-    fs,
-    path::Path,
     process::{Output, Stdio},
+    str,
 };
 
 use tokio::{process::Command, task};
 
-pub(super) async fn detect_alternative_targets(target: &str) -> impl Iterator<Item = String> {
+pub(super) async fn detect_targets(target: String) -> Vec<String> {
     let (prefix, postfix) = target
         .rsplit_once('-')
         .expect("unwrap: target always has a -");
@@ -37,71 +36,81 @@ pub(super) async fn detect_alternative_targets(target: &str) -> impl Iterator<It
                 .expect("unwrap: target always has a - for cpu_arch")
                 .0;
 
-            let has_glibc = task::spawn({
+            let cpu_arch_suffix = cpu_arch.replace('_', "-");
-                let glibc_path = format!("/lib/ld-linux-{cpu_arch}.so.1");
-                async move { is_gnu_ld(&glibc_path).await }
-            });
 
-            let distro_if_has_non_std_glibc = task::spawn(async {
+            let handles: Vec<_> = [
-                if is_gnu_ld("/usr/bin/ldd").await {
+                format!("/lib/ld-linux-{cpu_arch_suffix}.so.2"),
-                    get_distro_name().await
+                format!("/lib/{cpu_arch}-linux-gnu/ld-linux-{cpu_arch_suffix}.so.2"),
-                } else {
+                format!("/usr/lib/{cpu_arch}-linux-gnu/ld-linux-{cpu_arch_suffix}.so.2"),
-                    None
+            ]
+            .into_iter()
+            .map(|p| AutoAbortHandle(tokio::spawn(is_gnu_ld(p))))
+            .collect();
+
+            let has_glibc = async move {
+                for mut handle in handles {
+                    if let Ok(true) = (&mut handle.0).await {
+                        return true;
+                    }
                 }
-            });
 
-            let distro_if_has_musl_dynlib = if get_ld_flavor(&format!(
+                false
-                "/lib/ld-musl-{cpu_arch}.so.1"
+            }
-            ))
+            .await;
-            .await
-                == Some(Libc::Musl)
-            {
-                get_distro_name().await
-            } else {
-                None
-            };
 
             [
-                has_glibc
+                has_glibc.then(|| format!("{cpu_arch}-unknown-linux-gnu{abi}")),
-                    .await
-                    .unwrap_or(false)
-                    .then(|| format!("{cpu_arch}-unknown-linux-gnu{abi}")),
-                distro_if_has_non_std_glibc
-                    .await
-                    .ok()
-                    .flatten()
-                    .map(|distro_name| format!("{cpu_arch}-{distro_name}-linux-gnu{abi}")),
-                // Fallback for Linux flavors like Alpine, which has a musl dyn libc
-                distro_if_has_musl_dynlib
-                    .map(|distro_name| format!("{cpu_arch}-{distro_name}-linux-musl{abi}")),
                 Some(musl_fallback_target()),
             ]
         }
-        Libc::Android | Libc::Unknown => [
+        Libc::Android | Libc::Unknown => [Some(target.clone()), Some(musl_fallback_target())],
-            Some(target.to_string()),
-            Some(musl_fallback_target()),
-            None,
-            None,
-        ],
     }
     .into_iter()
     .flatten()
+    .collect()
 }
 
-async fn is_gnu_ld(cmd: &str) -> bool {
+async fn is_gnu_ld(cmd: String) -> bool {
-    get_ld_flavor(cmd).await == Some(Libc::Gnu)
+    get_ld_flavor(&cmd).await == Some(Libc::Gnu)
 }
 
 async fn get_ld_flavor(cmd: &str) -> Option<Libc> {
-    Command::new(cmd)
+    let Output {
+        status,
+        stdout,
+        stderr,
+    } = Command::new(cmd)
         .arg("--version")
         .stdin(Stdio::null())
         .output()
         .await
-        .ok()
+        .ok()?;
-        .and_then(|Output { stdout, stderr, .. }| {
+
-            Libc::parse(&stdout).or_else(|| Libc::parse(&stderr))
+    const ALPINE_GCOMPAT: &str = r#"This is the gcompat ELF interpreter stub.
-        })
+You are not meant to run this directly.
+"#;
+
+    if status.success() {
+        // Executing glibc ldd or /lib/ld-linux-{cpu_arch}.so.1 will always
+        // succeeds.
+        String::from_utf8_lossy(&stdout)
+            .contains("GLIBC")
+            .then_some(Libc::Gnu)
+    } else if status.code() == Some(1) {
+        // On Alpine, executing both the gcompat glibc and the ldd and
+        // /lib/ld-musl-{cpu_arch}.so.1 will fail with exit status 1.
+        if str::from_utf8(&stdout).as_deref() == Ok(ALPINE_GCOMPAT) {
+            // Alpine's gcompat package will output ALPINE_GCOMPAT to stdout
+            Some(Libc::Gnu)
+        } else if String::from_utf8_lossy(&stderr).contains("musl libc") {
+            // Alpine/s ldd and musl dynlib will output to stderr
+            Some(Libc::Musl)
+        } else {
+            None
+        }
+    } else {
+        None
+    }
 }
 
 #[derive(Eq, PartialEq)]
@@ -112,37 +121,10 @@ enum Libc {
     Unknown,
 }
 
-impl Libc {
+struct AutoAbortHandle<T>(task::JoinHandle<T>);
-    fn parse(output: &[u8]) -> Option<Self> {
+
-        let s = String::from_utf8_lossy(output);
+impl<T> Drop for AutoAbortHandle<T> {
-        if s.contains("musl libc") {
+    fn drop(&mut self) {
-            Some(Self::Musl)
+        self.0.abort();
-        } else if s.contains("GLIBC") {
-            Some(Self::Gnu)
-        } else {
-            None
-        }
-    }
-}
-
-async fn get_distro_name() -> Option<String> {
-    task::spawn_blocking(get_distro_name_blocking)
-        .await
-        .ok()
-        .flatten()
-}
-
-fn get_distro_name_blocking() -> Option<String> {
-    match fs::read_to_string("/etc/os-release") {
-        Ok(os_release) => os_release
-            .lines()
-            .find_map(|line| line.strip_prefix("ID=\"")?.strip_suffix('"'))
-            .map(ToString::to_string),
-        Err(_) => (Path::new("/etc/nix/nix.conf").is_file()
-            && ["/nix/store", "/nix/var/profiles"]
-                .into_iter()
-                .map(Path::new)
-                .all(Path::is_dir))
-        .then_some("nixos".to_string()),
     }
 }

crates/detect-targets/src/main.rs

@@ -0,0 +1,17 @@
+use std::io;
+
+use detect_targets::detect_targets;
+use tokio::runtime;
+
+fn main() -> io::Result<()> {
+    let targets = runtime::Builder::new_current_thread()
+        .enable_all()
+        .build()?
+        .block_on(detect_targets());
+
+    for target in targets {
+        println!("{target}");
+    }
+
+    Ok(())
+}

justfile

@@ -297,6 +297,9 @@ package-prepare: build package-dir
     just get-output detect-wasi{{output-ext}} packages/prep
     -just get-output detect-wasi.dSYM packages/prep
 
+    just get-output detect-targets{{output-ext}} packages/prep
+    -just get-output detect-targets.dSYM packages/prep
+
 # when https://github.com/rust-lang/cargo/pull/11384 lands, we can use
 # -just get-output cargo_binstall.dwp packages/prep
 # underscored dwp name needs to remain for debuggers to find the file properly
@@ -308,6 +311,9 @@ package-prepare: build package-dir
     just get-output detect-wasi packages/prep
     -cp {{output-folder}}/deps/detect_wasi-*.dwp packages/prep/detect_wasi.dwp
 
+    just get-output detect-targets packages/prep
+    -cp {{output-folder}}/deps/detect_target-*.dwp packages/prep/detect_target.dwp
+
 # underscored pdb name needs to remain for debuggers to find the file properly
 # read from deps because sometimes cargo doesn't copy the pdb to the output folder
 [windows]
@@ -318,6 +324,9 @@ package-prepare: build package-dir
     just get-output detect-wasi.exe packages/prep
     -just get-output deps/detect_wasi.pdb packages/prep
 
+    just get-output detect-targets.exe packages/prep
+    -just get-output deps/detect_target.pdb packages/prep
+
 # we don't get dSYM bundles for universal binaries; unsure if it's even a thing
 [macos]
 lipo-prepare: package-dir
@@ -335,6 +344,11 @@ lipo-prepare: package-dir
     just target=x86_64h-apple-darwin get-output detect-wasi{{output-ext}} packages/prep/x64h
     lipo -create -output packages/prep/detect-wasi{{output-ext}} packages/prep/{arm64,x64,x64h}/detect-wasi{{output-ext}}
 
+    just target=aarch64-apple-darwin get-output detect-targets{{output-ext}} packages/prep/arm64
+    just target=x86_64-apple-darwin get-output detect-targets{{output-ext}} packages/prep/x64
+    just target=x86_64h-apple-darwin get-output detect-targets{{output-ext}} packages/prep/x64h
+    lipo -create -output packages/prep/detect-targets{{output-ext}} packages/prep/{arm64,x64,x64h}/detect-targets{{output-ext}}
+
     rm -rf packages/prep/{arm64,x64,x64h}
 
 
@@ -370,6 +384,7 @@ repackage-lipo: package-dir
 
     lipo -create -output packages/prep/{{output-filename}} packages/prep/{arm64,x64,x64h}/{{output-filename}}
     lipo -create -output packages/prep/detect-wasi packages/prep/{arm64,x64,x64h}/detect-wasi
+    lipo -create -output packages/prep/detect-targets packages/prep/{arm64,x64,x64h}/detect-targets
 
     ./packages/prep/{{output-filename}} -vV
 

test-detect-targets-musl.sh

@@ -0,0 +1,20 @@
+#!/bin/ash
+
+# shellcheck shell=dash
+
+set -exuo pipefail
+
+TARGET=${1?}
+
+[ "$(detect-targets)" = "$TARGET" ]
+
+apk update
+apk add gcompat
+
+ls -lsha /lib
+
+GNU_TARGET=$(echo "$TARGET" | sed 's/musl/gnu/')
+
+[ "$(detect-targets)" = "$(printf '%s\n%s' "$GNU_TARGET" "$TARGET")" ]
+
+echo